This is usually due to Clan Castle troops being deployed in battle.

The clan crest that appears next to the troops in the battle log tells you that your enemy has used their Clan Castle troops in the attack. Take into account that all troops used in battle including the ones from the Clan Castle will appear together in the 'defense log' list. This means that the player can attack you with a maximum 240 troops plus those that they have in their Clan Castle (up to 35).

Clan Castle troops will not be listed separately, but instead automatically added to the rest of the troops.